User manual

Information Commands 26
Spanning Tree information
The following command displays Spanning Tree information:
show spanning-tree stp <1-32> information
Command mode: All
------------------------------------------------------------------
upfast disabled, update 40
------------------------------------------------------------------
Spanning Tree Group 1: On (STP/PVST+)
VLANs: 1
Current Root: Path-Cost Port Hello MaxAge FwdDel Aging
8000 00:02:a5:d1:0f:ed 8 20 2 20 15 180
Parameters: Priority Hello MaxAge FwdDel Aging
32768 2 20 15 180
Port Priority Cost FastFwd State Designated Bridge Des Port
---- -------- ---- -------- ---------- --------------------- -------
1 0 0 n FORWARDING *
2 0 0 n FORWARDING *
3 0 0 n FORWARDING *
The switch software uses the IEEE 802.1d Spanning Tree Protocol (STP). If RSTP/MSTP is turned on, see the
“Rapid Spanning Tree information” section for Spanning Tree Group information. In addition to seeing if STP is
enabled or disabled, you can view the following STP bridge information:
• Status of Uplink Fast (upfast)
• Current root MAC address
• Path cost
• Port
• Hello interval
• Maximum age value
• Forwarding delay
• Aging time
You can also refer to the following port-specific STP information:
• Port number and priority
• Cost
• State
• Port Fast Forwarding state
• Designated bridge
• Designated port
The following table describes the STP parameters.
Table 19 STP parameters
Parameter Description
Current Root Shows information about the root bridge for the Spanning Tree. Information includes the
priority (hex) and MAC address of the root.
Path-Cost Path-cost is the total path cost to the root bridge. It is the summation of the path cost
between bridges (up to the root bridge).
Port The current root port refers to the port on the switch that receives data from the current root.
Zero (0) indicates the root bridge of the STP.
Priority
(bridge)
The bridge priority parameter controls which bridge on the network will become the STP root
bridge.
Hello The hello time parameter specifies, in seconds, how often the root bridge transmits a
configuration bridge protocol data unit (BPDU). Any bridge that is not the root bridge uses
the root bridge hello value.
MaxAge The maximum age parameter specifies, in seconds, the maximum time the bridge waits
without receiving a configuration bridge protocol data unit before it reconfigures the STP
network.